Did the Facebook robots both want everything but the balls?
Not sure if you've gone through FAIR's blog post about these negotiating bots and the research behind them.


  Did the Facebook robots both want everything but the balls?


Yes. You are right.  You can refer to the gif in FAIR's blog post. Here, the chat goes on between 2 bots, where one wants only balls, and the other offers 1 ball and a hat. And this bot re-iterates that it wants only the balls. And they negotiate for some time till they reach a consensus.


  Perhaps these two are not such bad negotiators after all?


The fact that the FAIR labs have open-sourced the code means that they came a fairly long way in this research.  They also published the research paper. The example on the repo's README also cites the balls-and-hats negotiation example.